1,636 research outputs found

    Seasonal variations in incidence and maternal-fetal outcomes of gestational diabetes.

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    AIMS: To determine whether the neonatal and delivery outcomes of gestational diabetes vary seasonally in the context of a relatively cool temperate climate. METHODS: A retrospect cohort of 23 735 women consecutively delivering singleton, live-born term infants in a single tertiary obstetrics centre in the UK (2004-2008) was identified. A total of 985 (4.1%) met the diagnostic criteria for gestational diabetes. Additive dynamic regression models, adjusted for maternal age, BMI, parity and ethnicity, were used to compare gestational diabetes incidence and outcomes over annual cycles. Outcomes included: random plasma glucose at booking; gestational diabetes diagnosis; birth weight centile; and delivery mode. RESULTS: The incidence of gestational diabetes varied by 30% from peak incidence (October births) to lowest incidence (March births; P=0.031). Ambient temperature at time of testing (28 weeks) was strongly positively associated with diagnosis (P<0.001). Significant seasonal variation was evident in birth weight in gestational diabetes-affected pregnancies (average 54th centile June to September; average 60th centile December to March; P=0.027). Emergency Caesarean rates also showed significant seasonal variation of up to 50% (P=0.038), which was closely temporally correlated with increased birth weights. CONCLUSIONS: There is substantial seasonal variation in gestational diabetes incidence and maternal-fetal outcomes, even in a relatively cool temperate climate. The highest average birth weight and greatest risk of emergency Caesarean delivery occurs in women delivering during the spring months. Recognizing seasonal variation in neonatal and delivery outcomes provides new opportunity for individualizing approaches to managing gestational diabetes.Catherine Aiken is supported by an Isaac Newton Trust/Wellcome Trust ISSF/ University of Cambridge Joint Research Grant. Claire Meek receives salary funding from the Diabetes UK Harry Keen Intermediate Clinical Fellowship (17/0005712). The funders have had no role in study design, data collection, data analysis, manuscript preparation and/or publication decisions

    Noncollinear paramagnetism of a GaAs two-dimensional hole system.

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    We have performed transport measurements in tilted magnetic fields in a two-dimensional hole system grown on the surface of a (311)A GaAs crystal. A striking asymmetry of Shubnikov-de Haas oscillations occurs upon reversing the in-plane component of the magnetic field along the low-symmetry [2[over ¯]33] axis. As usual, the magnetoconductance oscillations are symmetric with respect to reversal of the in-plane field component aligned with the high-symmetry [011[over ¯]] axis. Our observations demonstrate that an in-plane magnetic field can generate an out-of-plane component of magnetization in a low-symmetry hole system, creating new possibilities for spin manipulation.This work was supported by the Australian Research Council (ARC) under the DP scheme and by the NSF under Grant No. DMR-1310199. ARH acknowledges an ARC DOR award.This is the accepted manuscript. The final version is available from APS at http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.113.236401

    Non-destructive imaging of buried electronic interfaces using a decelerated scanning electron beam

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    Recent progress in nanotechnology enables the production of atomically abrupt interfaces in multilayered junctions, allowing to increase the number of transistors in a processor, as known as Moore’s law, for example. However, uniform electron transport has never been achieved across the entire interfacial area in junctions due to the existence of local defects, causing local heating and reduction in transport efficiency. To date, junction uniformity has been predominantly assessed by cross-sectional transmission electron microscopy, which requires slicing and milling processes with potentially introducing additional damage and deformation. It is therefore essential to develop an alternative non-destructive method. Here we show a non-destructive technique using scanning electron microscopy to map buried junction properties. By controlling the electron-beam energy, we demonstrate the contrast imaging of local junction resistances at a controlled depth. This technique can be applied to any buried junctions, from conventional semiconductor and metal devices to organic devices

    Enhanced progesterone support during stimulated cycles of transvaginal follicular aspiration improves bovine in vitro embryo production

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    The in vitro production (IVP) of cattle embryos requires that germinal-vesicle stage oocytes undergo a period of maturation in vitro prior to fertilization and culture to the blastocyst stage. Success of IVP in taurine cattle is enhanced following ovarian stimulation prior to oocyte retrieval (OPU), particularly if preceded by a short period of FSH withdrawal (‘coasting’). However, evidence regarding the importance of progesterone (P4) support during OPU-IVP is equivocal. The current study, therefore, determined the effects of increased peripheral P4 concentrations during FSH-stimulated (‘coasted’) cycles of OPU. Progesterone support was provided by either an active corpus luteum (CL) and/or one of two intravaginal P4 releasing devices (i.e., CIDR® [1.38g P4] or PRID® Delta [1.55g P4]). Expt. 1 established an initial estrus prior to OPU, allowing CL formation (single luteal phase) spanning the first two of five cycles of OPU; the remaining three cycles were supported by either a CIDR® or PRID® Delta. Expt. 2 commenced with two cycles of dominant follicle removal (including prostaglandin F2α) undertaken seven days apart prior to six cycles of OPU. The absence of a CL meant that these cycles were supported only by a CIDR® or PRID® Delta. As each experiment involved several sequential cycles of OPU, the cumulative effects of device use on vaginal discharges were also assessed. Each experiment involved 10 sexually mature Holstein heifers. In the absence of a CL, peak plasma P4 concentrations were greater (P = 0.002) for the PRID® Delta (4.3 ± 0.22) than for the CIDR® (2.9 ± 0.22). In Expt. 1 there was an interaction (P < 0.05) between CL presence at OPU and P4 device on Day 8 blastocyst yields, indicating an effect of P4 device only when the CL was absent. The percentage hatching/hatched blastocysts of matured oocytes for the CIDR® and PRID® Delta was 44.3 ± 5.04 and 41.0 ± 5.40 in the presence, and 17.1 ± 3.48 and 42.2 ± 3.76 in the absence, of a CL (P = 0.018). Combined analyses of data from Expt. 1 and 2, when no CL was present, confirmed that Day 8 blastocyst yields were greater (P = 0.022) for the PRID® Delta than the CIDR®. Vaginal discharge scores were higher (P < 0.001) for the PRID® Delta than the CIDR® in Expt. 1 but not in Expt 2; however scores were low, did not increase with repeated use, and thus were deemed of no clinical or welfare concern. In conclusion, enhanced P4 support during FSH-stimulated cycles of OPU-IVP can improve in vitro embryo development

    On staying grounded and avoiding Quixotic dead ends

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    The 15 articles in this special issue on The Representation of Concepts illustrate the rich variety of theoretical positions and supporting research that characterize the area. Although much agreement exists among contributors, much disagreement exists as well, especially about the roles of grounding and abstraction in conceptual processing. I first review theoretical approaches raised in these articles that I believe are Quixotic dead ends, namely, approaches that are principled and inspired but likely to fail. In the process, I review various theories of amodal symbols, their distortions of grounded theories, and fallacies in the evidence used to support them. Incorporating further contributions across articles, I then sketch a theoretical approach that I believe is likely to be successful, which includes grounding, abstraction, flexibility, explaining classic conceptual phenomena, and making contact with real-world situations. This account further proposes that (1) a key element of grounding is neural reuse, (2) abstraction takes the forms of multimodal compression, distilled abstraction, and distributed linguistic representation (but not amodal symbols), and (3) flexible context-dependent representations are a hallmark of conceptual processing

    Nonlinear Sigma Model for Disordered Media: Replica Trick for Non-Perturbative Results and Interactions

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    In these lectures, given at the NATO ASI at Windsor (2001), applications of the replicas nonlinear sigma model to disordered systems are reviewed. A particular attention is given to two sets of issues. First, obtaining non-perturbative results in the replica limit is discussed, using as examples (i) an oscillatory behaviour of the two-level correlation function and (ii) long-tail asymptotes of different mesoscopic distributions. Second, a new variant of the sigma model for interacting electrons in disordered normal and superconducting systems is presented, with demonstrating how to reduce it, under certain controlled approximations, to known ``phase-only'' actions, including that of the ``dirty bosons'' model.Comment: 25 pages, Proceedings of the NATO ASI "Field Theory of Strongly Correlated Fermions and Bosons in Low - Dimensional Disordered Systems", Windsor, August, 2001; to be published by Kluwe

    Estimating the effects of COVID-19 on essential health services utilization in Uganda and Bangladesh using data from routine health information systems

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    Background Since March 2020, the coronavirus disease 2019 (COVID-19) pandemic has been a major shock to health systems across the world. We examined national usage patterns for selected basic, essential health services, before and during the COVID-19 pandemic in Uganda and Bangladesh, to determine whether COVID-19 affected reporting of service utilization and the use of health services in each country. Methods We used routine health information system data since January 2017 to analyze reporting and service utilization patterns for a variety of health services. Using time series models to replicate pre-COVID-19 trajectories over time we estimated what levels would have been observed if COVID-19 had not occurred during the pandemic months, starting in March 2020. The difference between the observed and predicted levels is the COVID-19 effect on health services. Results The time trend models for Uganda and Bangladesh closely replicated the levels and trajectories of service utilization during the 38 months prior to the COVID-19 pandemic. Our results indicate that COVID-19 had severe effects across all services, particularly during the first months of the pandemic, but COVID-19 impacts on health services and subsequent recovery varied by service type. In general, recovery to expected levels was slow and incomplete across the most affected services. Conclusion Our analytical approach based on national information system data could be very useful as a form of surveillance for health services disruptions from any cause leading to rapid responses from health service managers and policymakers

    Estimating the effects of COVID-19 on essential health services utilization in Uganda and Bangladesh using data from routine health information systems

    Get PDF
    BackgroundSince March 2020, the coronavirus disease 2019 (COVID-19) pandemic has been a major shock to health systems across the world. We examined national usage patterns for selected basic, essential health services, before and during the COVID-19 pandemic in Uganda and Bangladesh, to determine whether COVID-19 affected reporting of service utilization and the use of health services in each country.MethodsWe used routine health information system data since January 2017 to analyze reporting and service utilization patterns for a variety of health services. Using time series models to replicate pre-COVID-19 trajectories over time we estimated what levels would have been observed if COVID-19 had not occurred during the pandemic months, starting in March 2020. The difference between the observed and predicted levels is the COVID-19 effect on health services.ResultsThe time trend models for Uganda and Bangladesh closely replicated the levels and trajectories of service utilization during the 38 months prior to the COVID-19 pandemic. Our results indicate that COVID-19 had severe effects across all services, particularly during the first months of the pandemic, but COVID-19 impacts on health services and subsequent recovery varied by service type. In general, recovery to expected levels was slow and incomplete across the most affected services.ConclusionOur analytical approach based on national information system data could be very useful as a form of surveillance for health services disruptions from any cause leading to rapid responses from health service managers and policymakers

    Cardiovascular risk assessment scores for people with diabetes: a systematic review

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    People with type 2 diabetes have an increased risk of cardiovascular disease (CVD). Multivariate cardiovascular risk scores have been used in many countries to identify individuals who are at high risk of CVD. These risk scores include those originally developed in individuals with diabetes and those developed in a general population. This article reviews the published evidence for the performance of CVD risk scores in diabetic patients by: (1) examining the overall rationale for using risk scores; (2) systematically reviewing the literature on available scores; and (3) exploring methodological issues surrounding the development, validation and comparison of risk scores. The predictive performance of cardiovascular risk scores varies substantially between different populations. There is little evidence to suggest that risk scores developed in individuals with diabetes estimate cardiovascular risk more accurately than those developed in the general population. The inconsistency in the methods used in evaluation studies makes it difficult to compare and summarise the predictive ability of risk scores. Overall, CVD risk scores rank individuals reasonably accurately and are therefore useful in the management of diabetes with regard to targeting therapy to patients at highest risk. However, due to the uncertainty in estimation of true risk, care is needed when using scores to communicate absolute CVD risk to individuals
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